Conventionally, as a semiconductor device that includes a bridge circuit provided with semiconductor switching elements respectively disposed at an upper arm and a lower arm, a power converter that includes three-phase inverter circuit of a U-phase, a V-phase, and a W-phase are known (see Patent Literature 1). The power converter includes power semiconductor elements disposed at an upper arm and a lower arm of each of the three phases and converts a direct current into an alternating current by switching operations of the power semiconductor elements.
In the power converter, a quadrangular plate-shaped parallel conductor in which a positive electrode terminal and a negative electrode terminal are bonded while sandwiching an insulating film is used as an input terminal. At one side of the parallel conductor, an input bus bar constituting a part of a positive electrode side wiring (hereafter, referred to as a positive electrode input bus bar) and an input bus bar constituting a part of a negative electrode side wiring (hereafter, referred to as a negative electrode input bus bar) are extended in parallel with each other while being separated from each other by a predetermined distance. In addition, the power semiconductor elements of the upper arms for the three phases are disposed at equal intervals on the positive electrode input bus bar, and the power semiconductor elements of the lower arms for the three phases are disposed at equal intervals on the negative electrode input bus bar. Then, output bus bars for the three phases are extended perpendicular to the input bus bars so as to connect the upper arms and the lower arms of the respective phases. The upper arms and the lower arms of the respective phases are connected to a load supplied with the alternating current through the output bus bars.
In addition, Patent Literature 2 suggests a semiconductor device that includes a plurality of power semiconductor elements and constitutes a power converter converting a direct current into an alternating current based on switching operations of the plurality of power semiconductor elements. The semiconductor device includes a positive electrode terminal (a positive electrode side main electrode) and a negative electrode terminal (a negative electrode side main electrode) protruding in a perpendicular direction from a side of a case of the semiconductor device having a substantially quadrangular plate shape. The positive electrode terminal and the negative electrode terminal are formed of plate-shaped electrodes. The plate-shaped electrodes constituting the positive electrode terminal and the negative electrode terminal are bonded to each other while sandwiching an insulation member to form a plate-shaped conductor (a parallel conductor). Positions of leading edges of the positive electrode terminal and the negative electrode terminal are shifted, and the leading edge of the negative electrode terminal protrudes more than the leading edge of the positive electrode terminal so as to be further away from the case.
The positive electrode terminal and the negative electrode terminal configured as described above are connected to a positive electrode side direct current bus bar and a negative electrode side direct current bus bar and are connected to a smoothing capacitor through the bus bars. Specifically, the positive electrode side direct current bus bar and the negative electrode side direct current bus bar are formed of a plate-shaped conductor and a leading edge of the positive electrode side direct current bus bar protrudes more than a leading edge of the negative electrode side direct current bus bar. When the negative electrode side direct current bus bar is disposed on the negative electrode terminal, which protrudes more between both terminals of the semiconductor, the leading edge of the positive electrode side direct current bus bar, which protrudes more than the negative electrode side direct current bus bar, is disposed on the positive electrode terminal. Base on this, at the leading edge of the negative electrode terminal and the leading edge of the positive electrode side direct current bus bar, the negative electrode terminal and the negative electrode side direct current bus bar are brazed, and the positive electrode terminal and the positive electrode side direct current bus bar are brazed so as to provide electrical and mechanical connections.